Mechanical silent tappet



DeC- 5, 1950 c. L. sTANcLlFF `2,532,346

MECHANICAL SILENT TAPPET Filed June 18, 1946 3 Sheets-Sheet l INVENTOR.

C; IFTON LS1-ANCI.. H-F

BY M,

ATTORNEYS Dec. 5, 1950 c. L.. s'rANcLlFF 2,532,346

MECHANICAL SILENT TAPPET Filed June 18, 1946 3 Sheets-Sheet 2IVIIIIIIIIIIIIIL INVENTOR. CLIFTON L .STANCLIFF AT ToRNEYs Dem 5, 1950c. l.. sTANcLlFF 2,532,346

MECHANICAL SILENT TAPPET Filed June 18, 1946 5 Sheets-Sheet 3 1. -13.1 rv l, f N 47 ZV TTU.

46 l 51 39* f 2V Y a: l l 9 S 40 L mw@ V1' INVENTmL CLU-TON L .STANCLJFFmm l 'P AT TOR NEWS,

Patented Dec. 5, 1950 UNITED STATES PATENT GFFIC MECHANICAL SILENTTAPPET Clifton L. Stancliif, Bakersfield, Calif.

Application June 18, 1946, Serial No. 677,552

13 Claims. l

An object of my invention is to provide a mechanical silent tappet whichis an improvement over the form of my invention shown in my Patent No.2,493,783, dated January 1G, 1950. In the copending case, I disclose thespring means for rotating the two parts of the silent tappet as beingdisposed exteriorly of the parts. In the present form of the inventionthe spring means for rotating one part with respect to the other isconfined within the area occupied by the two parts.

In all of the modiiications illustrated in the present case, the twoparts of the device have centering means for holding them in properrelation `with the valve stem and with the valve tappet. The mechanicalsilent tap-pet is waferlike in appearance and can be slipped between thevalve stem and tappet or between the push rod and rocker arm, or betweenthe valve stem and rocker arm, and will remain in position Witnout anyauxiliary fastening means being necessary.

The device is extremely simple in construction and is designed to bestamped out from sheet metal.

Other objects and advantages will appear in the following specification,and the novel features of the device will be particularly pointed out inthe appended claims. i

My invention is illustrated in the accompanying drawings forming a partof this application, in which:

Figure l is a top plan view of the silent tappet;

Figure 2 is a top plan view of the upper plate;

Figure 3 is a top plan view of the lower plate;

Figure 4 is a section taken along the line IV-IV of Figure 1;

Figure 5 is a section taken along the line V--V of Figure l;

Figure 6 is a transverse section taken along the line VI-VI of Figure l;

Figure 7 is a view similar to Figure 6, but shows the two parts of thedevice in a slightly separated position; i

Figure 8 is a top plan view of a modified form of the invention;

Figure 9 is a transverse section taken along the line IX-IX of Figure 8;

Figure l0 is a top plan view o the lower plate; Figure ll is a top planview of the upper plate;

Figure 12 is a section taken along the line .XIL-XII of Figure 8;

Figure 13 is a top plan View of another modified form of the invention;

2 Figure 14 is a transverse section taken along the line XIVXIV ofFigure 13;

Figure 15 is a top plan View of the lower plate; Figure 16 is a sectiontaken along the line XVI- XVI of Figure 13;

Figure 17 is a section taken along line XVIL-XVII of Figure 13;

Figure 18 is a view similar to Figure 17 but shows the parts slightlyseparated; and

Figure 19 is a top plan View of the upper plate.

While I have shown only the preferred forms of my invention, it shouldbe understood that various changes or modiiications may be made withinthe scope of the appended claims without departing from the spirit andscope of the invention.

In carrying out my invention, I provide a mechanical silent tappetcomprising two disc-shaped plates, an upper plate indicated at A inFigure 2, and a lower plate indicated at B in Figure 3. The device isdesigned to be stamped out by means of a punch press and both Figures 1:and r2 show the upper plate provided with a plurality ofA raisedportions I when looking at the top of the plate, these portions beingprovided with camshaped undersurfaces 2 as illustrated in Figure 5. Itwillbe noted that these cam-shaped surfaces have a gradual arc portion2a and an abrupt curved portion 2b. The raised portions l are arrangedin a circle about a common center 3 and as many of these portions asdesired may be provided. In Figure 2 I show twelve of the raisedportions, although I do not wish to be conned to any exact number.

Within the boundary deined by the circle of raised portionsA l, Iprovide a second group of semi-cylindrical raised portions t. In Figure4 the interior of the raised portions 4 are designed to receive theupper halves of coil springs 5. Each interior forms the upper half of aspring housing 6. The housing has a shoulder l' formed at one endagainst which an end of the spring 5 contacts and the other end of thehousing 6 has an inclined wall li. rlfhe raised semi-cylindricalportions i are arcuate in shape and are arranged in a circle whosecenter is the same center 3 for the raised portions I, see Figure 2.Referring to Figure 6, it will be seen that the upper plate A has acircumferential ange 9 that extends downwardly and this flange has aninwardly turned rim iii fora purpose presently to be described. It willbe seen that the entire upper plate is designed so that it can be punchpressed.

Figure 3 shows the top of the lower plate and this plate s provided witha plurality of depressions or recesses Il of a number equal to thenumber of raised portions I. The recesses I I have cam-shaped innersurfaces I2 designed to cooperate with the cam-shaped surfaces 2, seeFigure 5. Each surface I2 has a gradual arcuate portion I2a and anabrupt curve IZb. Figure 5 indicates how the gradual arc portion 2a, isdisposed at the opposite side of a ball C from that oi the gradual arcportion 52a. When the disc A is rotated in thev directionA or thearrov-.zy shown in Figure iand'the disc B` rotated in the oppositedirection, the ball C will act on the curved cam surfaces 2a and Ia forseparating discs A and B a slight distance One from the otheri Againreferring to Figure 3, it will be seen thatthe plate B has a pluralityof elongated and arcuate shaped recesses I3 that are semicircular incross section. These recesses cooperate with the` spring-receivinghousings to accommodate the lower.A halves of: the coil springs 5. Eachrecess I3 has a shoulder i against whichwthe'adjacent endof. the spring5 contacts andthe opposite end ofy eachv recess is provided with aninclined wall I5. Figure 4 illustrates how the; springs 5 are receivedwithin the cooperating portions 5 and I3 and how the ends of the springscontact with the shoulders 'I and Ill for yieldinglyv urging the discslAand B in oppositek directions.

n In; assembling the parts, the. balls C areplaced inl the recesses.Hand the springs 5 are placed in, the recess I3, The upper plate A isnow moved down upontheilower plate, and the springs are received in-lthe upper` spring'hcusing 6V while the balisgare received inthe cavities2. Therim Il is formed on the ange 9 after the plate A is mounted ontheplate B. A felt washer I6 may be,` placed in a. groove il that extendsaround theperiphery of .ther pla-teB. This washer is for the. purpose;Aof retaining; any oil that; may' be forced between -twoplates. Itwill benotedrfrom- Figures 3, 6 and '7 that the lower plateA has a centraloilopening I8 and this opening registers with an axial bore I9` provided inthe tappet pli-1g D.-

From'the foregoingdescription of thevarious partsof thedevice,the*operation thereofmay be readily understood.

The wafer thin device is placed between the tappet plugvor lift D andthe lower end of a valve 'f stem E, or between theppush rod'` and rockerarm, orf-.sternA and rocker arm on an overhead` valve motor. The.outersurfaces on the-lower plate B which form the recesses i3 act as acentering meansforthe plateB- on thetappet plug or lift as clearly shownin Figures-l 6.and 7. In like manner the projections or, raised portionsIv on tha upper: plate` Av act as a centering means for correctlypositioning the device with respect to the valve sternE. In mounting thedevice in place all thatis, necessaryv istolinsert it between-r thetappet-Dandvalve stern E. No fasteningmeans of any-kind is necessary.

During-the operation of theengine itis asfsurnedsthat ,during theinterval ci" y rest whenl the Valve isseated and the tappet plugk is inits lower.- most, position', theitwo plates A and` B; will have theircentral portions.v spaced slightly apart. When the tappetliftsfthevalve-stem thev springs 5i wllrstyield andnpermit thetop plateAV torotatewi-th-respect to thebottom plate B until the,centralportionsAI andBI contact with each other. The ballsC ,will roll downl to the. lowestportions of,lthe cam surfaces I2, while` at the same timethehighest,portionssot the cam sur-` faces 2 will Contact with the topsof the balls to permit this movement. The two plates A and B willcontact with each other at the central portions AI and Bl before thevalve starts to lift. No metallic sound has been created during themovement of the central portions Ai and BI into contact with each otherbecause these portions already contact with the tappet and with thevalve stem and the initial movement really consists` in the. closing. oftheespaceibetween the central pla-teportions and aslight rotationalmovement between the two plates. rIhis is accompanied without anymetallic noise because of the gradual cam surface portions 2a and I2acausing the central plate portions to come together with a nlm ofoiltherebetween.

During the lifting of the valve by the tappet, the springs 5 are notused to lift the valve because the central plate portions A! and BIcontact each other and carry the entire load. As soon as the valvehascompleted its opening and closing moyement` and should the tappetcontinue to, move away from the valve stem end so as to forma spacetherebetween, the plate A will instantly lotate with respect to theplate B dueto the action of the springs 5 and will move thearcuate camsurfaces 2a, and I2a in the. directions of the arrows shown in Figure 5for causing the balls andv the. cam portions to spread the centralplateportions apart. Since this movement instantly.4 takes place, thereis no time period when the valve stemY end will, be spaced fromA theplate` A and therefore there will be no tappet noise.

The bore Iii: communicateswith a forced feed lubricating system, and theseparation ofthe two central plate portions, asin Figure 7, will permitlubrication under pressure to be` forced between the plates A` and B andlubricate the balls.V and the springs. A thin lm of lubricant W-ill formon the inner surfaces, of the two plates and this will permit relativerotation between` theplates the instant there is any separation betweenthe tappet and the valve stem end.

In the drawings ofFigures 1 to '7, inclusive, the

' device is shown on a greatly enlarged scale for clarity. Inactualpractice the material willbe to als ofY an inch thick. The tappet screwis adjusted to take care of the` thickness of' the two plates, so thatthe total distance between the tappet and valve stem will be .072 to.077; No-other changes arenecessary to be made; The valve stem'is'raisedto insertthe device.

The form shown in Figures 8 to 12, inclusive, is designed primarily fora Ford motor car engine. This -formis also of the punch press type; Thelower plate Vl?? is shown in Figures 9 and 10 and it will be seen thatthis plate is provided with a plurality of hemispherically shapedrecesses 20.' In addition thek rimY 2l ofthe platehas struck up portions'22 provided with radially extending shoulders 23; The top plate G hasa'centralportion 24 designed to rest on the central portion of the lowerplate. Figure 11 shows the top plate provided with a plurality ofspherical shaped recesses 255 that are designed to overlie andnor-Inally register with the, recessesY 2Q in the lower plate. Balls H areplaced in the, alignedirecesses and when the topA plate is rotatedwithrespect to the bottom one, the sphericalsurfaces of there/- cesses willride on'theiballs to cause them togseparatel the plates andautomatically takeup any spaceithat might existbetween the Fordlift'J'and the valve stem K.

The-top platehas an annular springfreceiving channel 21 formedadjacenttdits rim, this chan@l nel overlying the rim 2| of the lowerplate. Figure 11 shows projections 28 extending inwardly into thechannel, these projections providing flat radially extending shoulders2i) against which the ends of springs 30 bear. Figure 12 shows a portionof the channel 2l with its inwardly ex tending projection 28 and thespring 3G is indicated as contacting with the nat shoulder 2S. The otherend of the spring contacts with the shoulder' 23 formed by the upwardlyextending projection 22.

Figure 8 illustrates the assembled device while Figure 9 shows how therim 3l of the upper plate G extends beyond the channel 2l and enclosesthe periphery of the lower plate F. The portions 32 are struck inwardlyfrom the rim 3l and prevent the plate G from being entirely removed fromthe plate F. If desired, a felt washer 33 may be placed adjacent to therim 2 I, this washer or seal bearing against the rim 3l of the upperplate.

Ihis device operates in the same manner as that disclosed for the devicein Figures 1 to 7, inclusive. The springs Si) are placed outside of theballs H in this device rather than inside of the balls. The springs tendto rotate the two plates F and G with respect toeach other and to causethe balls H to act on the spherical surfaces 20 and 26 to move the twoplates apart as indicated in Figure 12 by the dash lines. The Ford valvestem K has a bushing 34 and a keeper 35. The silent mechanical tappet isplaced between the Ford lift and the valve stem. The flange of thekeeper 35 is received within the circular portion formed by the outersurface of the spring receiving channel 2l. The lower plate F has adepression 35 on its under surface that will fit the conical top of theFord lift J. No fastening means is necessary to secure the silent tappetin place. The device will clear the valve lifter guide shown at 3'?.

In Figures 13 to 19, inclusive, I show another modified form of silenttappet which makes use of cams rather than balls. In this form, thelower plate L has a central depression 38 on its under surface forreceiving the top of the tappet plunger or lift M. The upper plate N hasa central def pression 39 in its upper surface that receives the end ofthe valve stern P. The two plates L and N have the same outer diameterand a retaining ring 4i! is secured at di to the top plate and rotatablyand slidably receives the bottom plate. The ring di! has an inwardiyextending flange d2 that prevents the entire removal of the plate N fromthe plate L.

Referring to Figure l5, it will be seen that the bottom plate L has acircle of arcuate-shaped recesses 113 that are semicylindrical in crosssection. The top plate N has complimentary re cesses i4 that registerwith the recesses i3 in the manner shown in Figure 16. A coil spring 45is placed in each pair of registering recesses and one end of eachspring will bear against the shoulder t5 in the lower plate while theother end of the spring will bear against the shoulder 4l in the topplate. The springs tend to rotate the two plates with respect to eachother and to cause depending cams 48, that are carried by the undersurface of the top plate, to ride on cam surfaces 49 provided in theupper surface of the lower plate. Figure il illustrates the position ofone of the cams 48 when the two plates L and N are in contact with eachother. Figure l5 shows the lower plate provided with a plurality of camsurfaces 49, while Figures 13 and 19 illus 6 trate the top plate asbeing provided with a plurality of cams 48. In Figure 18 the two platesL and N have been moved apart a slight distance by the cams 48 riding upon the cam surfaces 49.

In operation this form of the invention performs in the same manner asthe other two forms, except that the cams 8 are integral with the topplate N and slide over the cam surfaces 49 in the lower plate. Anyspacing that might exist between the top of the tappet M and the bottomof the valve stem P will be automatically taken up by the instantmovement of the two plates away from each other, because of the springs45. This form of the device may be lubricated by a central bore 5l! inthe tappet conveying a lubricant through an opening 5l provided in thebottom plate L. When the plates are spaced apart, the lubricant williiow therebetween and will lubricate the opposed surfaces as well as thecam# shaped recesses 49 and the projections 48.

I claim:

1. A mechanical silent tappet comprising two disc-shaped membersarranged in confronting relation and adapted to be placed between anoperating part and an operated part of a valve-operating mechanism, theconfronting faces of the members having registering recesses withcamshaped surfaces that extend from the said faces to spaced distancestherefrom, a ball bearing placed in each pair of recesses, the pairs ofrecesses being arranged in a circle about the center of the members andthe cam surfaces of each pair being such that a relative rotationbetween the members in one direction will cause the balls to ride on thecam surfaces to separate the mem? bers, and spring means confined withinthe perimeters of the members for yieldingly urging them in thedirection just mentioned, said spring means being disposed within thearea dened by the ballbearing recesses and including a plurality ofarcuate-shaped cavities formed in each member, the cavities in onemember cooperating' with those in the other to provide pairs ofcavities, and a coil spring mounted in each cavity pair, each cavityhaving a face against which an end of the spring bears, the faces ineach pair contacting opposite ends of the spring, the springs yieldinglyexerting a rotative force on the members for causing the balls to rideon the cam surfaces to separate the members.

2. A mechanical silent tappet comprising `two disc-shaped members madeof sheet metal and having central portions arranged in confrontingrelation, each member having portions formed into cam-shaped recesses,the recesses in one member registering with those in the other to formpairs of ball-receiving compartments that are arranged in a circle whosecenter is the aligned centers of the members, balls placed in thecompartments, each member also having semi-cylindrical arcuate-shapedcavities formed therein, the cavities in one member registering withthose in the other to form pairs of springreceiving compartmentsarranged in a circle that lies within and is concentric to theIball-receiving compartments, springs mounted in the spring-receivingcompartments, the cavities in one member having shoulders bearingagainst one end of the springs and the cooperating cavities in the othermember having shoulders bearing against the other end of the springs.,the` springs yieldingly exerting a rotative force on the members forcausing the balls to ride on the cam surfaces to separate the members.

t. A mechanical silent tappet comprising two atsasae 'ifr disc-shapedmembersmade of sheet-metal :and having centralv portions arranged in'confronting relation, each member having portions `formedVinto-fcamshaped recesses, the recessesinone member registering withthose' in the other to form pairs of ball-receiving compartments thatare arranged in a circle whose centerl is the aligned centers of themembers, balls -placediin the compartments, each member also having-1semi-cylindrical arcuate-shaped cavities formed therein, the cavities inone member registering with those in the other to form pairs ofspring-receiving compartments arranged in a circlethat lies within andisconcentric tothe ball-receiving compartments,y springs mounted" inthefspring-receiving compartments, the` cavities in one member havingshoulders bearingv against one end of the springs and thecooperatingcavities in the other member having shoulders bearing against the otherendof the springs,

the springs yieldingly exerting a rotativey force on 'themembers Vforcausing the balls to -ride on the -cam surfaces to separate the members,one member having a peripheral rim for slidably` receiving: theperiphery of the other member, l

and means carried by the rim for limiting the separation between themembers.

`4.,A- mechanical silent tappet comprising two disc-shaped. members madeof sheet metal andl having central portions arranged in confronting.relation, each member having partial sphericalshaped recesses, therecesses in one member registeringwith those in the otherltoform-pairsof ballfreceiving compartments that are arranged in a circlewhose center is the aligned centers 0f themembers, balls placed in thecompartments, onemember having a circular spring,- receiving channelthat surrounds the circle of ballreceiving compartments, the channelhaving inwardly-extending stops, the other memberllhaving aportionforming a closure for the channel with stops extending inwardlyinto the. channel for cooperating with the other stops to provide pairsof` stops,.and coil'springslplaced inthe channel and having their endsbearing against the pairs of stops for yieldingly exerting airotativeforce on the members for causing the balls to ride on the cam surfacesof saidV recesses to separate the members.

5. A mechanical silent tappetv comprising two disc-shaped members madeof sheet metal and having central portions arrangedin confrontingrelation, eachmember having partial sphericalshaped recesses, therecesses in one member registering with those in the other to form pairsof ball-receiving compartments that arearrangedy in a circle whosecenter is theV alignedv centers of the members, balls placed in thecompartments, one member having a circular springreceiving channel thatsurrounds the circle' of ball-receiving compartments, the channel havinginwardly-extending stops, the other member having a portion forming aclosure for the channel with stops extending inwardly into the channelfor cooperatingwith the other stops to provide pairs of stops, coilsprings placed in the.y

channel and having their ends bearing against the pairs of stops foryieldingly exerting a rotative force on the members for causing thevballs to ride on the cam surfaces of said recesses` tov separate themembers, the channel having an` extended circular side for slidablyreceiving the periphery of the other member, and means carried by thecircular side for limiting the separation between the twomembers.

6i Aim'echancal silent tappetl comprising two Vii) til)

8; disc-shaped4 members yand having centra'lfporf' tions adapted tocontact each other so asto' transmitthrust from one member to`theother,` the membershaving centrally disposed recesses in theirouter'surfaces adapted toreceive an op;- erating and anoperated part ofaIvalve-actuating mechanism, both members having arcuate andsemi-cylindrical recesses in their confronting surfaces, theY recessesin one' memberY regl istering with those in the other substantially.-v

throughout their lengths to form pairs-otrecesses, coil springs receivedin the pairsof-frecesses and extending into both, one recess of eachpair having an end wall contactingwithv an end of the spring received inthe recess Yand the other recess of the same pairl having an end wallcontacting with the other end of thefsame spring; one member having aplurality of cams arranged in a circle `that encloses the pairs of;recesses, the other member having a plurality, of cam-shaped concavesurfaces that receive theV cams, said cams when at the lowest pointsofthe concave surfaces permitting the central-portions of said membersto contact each other, said' springs yieldingly exerting a rotativeforceon the, members for causing the cams-to rideonthe-con-` cavesurfaces for separating the members.

7. A mechanical silent tappet comprisingtwo disc-shaped members andhaving central portions adapted to contact each other so as to transmitthrust from one member to the other,

the members having centrally disposed-recessesl in their outer surfacesadapted to receive an operating and an operated part of` a valve--actuating mechanism, respectively, both mem/- bers having arcuate andsehn-cylindrical recesses in their confronting surfaces, the recesses inone member registering with those-inthe other substantiallythroughout-their lengths to form pairs of recesses, coil springsreceived in the pairs of recesses and extending into both, one recess ofeach pair having an end wall contacting with an end. ofthespringireceived in the recess and the other recess of the same pairhaving., an end wall contacting with the other end of the same spring,one member having a. plurality of cams arranged in a-circle thatencloses the pairs of recesses, the other member having aplurality. ofcam-shaped concave surfaces that receive the cams, said'cams when at thelowest points ofl the concave surfaces permitting the central portionsof said members to contact each other, said. springs yieldingly exertingarotative force on the members for causing the cams to ride on theconcave surfaces for separating the membersa ring carriedA bytheperiphery of one member and slidably receiving the periphery ofYtheother, and means carried by the ring for limiting the separationbetween the members.

8. A mechanical silent tappet comprising two disc-shaped membersarranged in confronting. relation, the members having centrally disposedrecesses in their outer surfaces adapted to receive an operating and anoperated part ora Valve-actuating mechanism` recesses in theirconfronting surfaces, the' re cessesA in one member registering withthose in the other substantially throughout their lengths to form pairsof recesses, coil springs received in the pairs of recesses andextending intov both, one recess of'each pair having an end Wallcontacting with an end of the spring received inv the recess and theother recess oi thesame pair' having an end wall contacting with theother endloi-v the same'spring, one'member having a respectively, both'members having arcuate and semi-cylindrical` plurality of cams arrangedin a circle that encloses the pairs of recesses, the other member havinga plurality of cam-shaped concave surfaces that receive the cams, saidsprings yieldingly exerting a rotative force on the members for causingthe cams to ride on the concave surfaces for separating members, a ringcarried by the periphery of one member and slidably receiving theperiphery of the other, and means carried by the ring for limiting theseparation between the members, the member contacting with one of saidparts of said mechanism having a lubricant receiving opening thereinthat registers with a lubricant bore in that part.

9. A. mechanical silent tappet comprising two wafer-like membersarranged one above the other in confronting relation and movable intoface-to-face contact so as to transmit thrust from one member directlyto 'the other, and adapted to be interposed between operating andoperated parts of a valve-actuating mechanism; the upper member having adepending annular iiange on its periphery having a dust-tight andsliding telescoping iit with the periphery of the lower member; theflange dening a downwardly-facing opening at its bottom through whichthe lower member is insertable; camming means connned within theperipheries of the members for separating them when one member isrotated relative to the other in one direction; the camming means beingshaped to gradually bring the members into sliding contacting relationwith a spiral movement when the direction of rotation is reversed; andspring means for rotating the members in the direction to separate themembers to maintain them continually in engagement with the operated andoperating parts, respectively, of the valve-actuating mechanism.

l0. A mechanical silent tappet comprising two wafer-like membersarranged one above the other in confronting relation, and adapted to beinterposed between operating and operated parts of a valve-actuatedmechanism; the upper member having a depending annular flange on itsperiphery having a dust-tight and sliding telescoping nt with theperiphery of the lower member; the flange defining a downwardly-facingopening at its bottom through which the lower member is insertable;camming means confined within the peripheries of the members forseparating them when one member is rotated re1- ative to the other inone direction; the camming means being shaped to gradually move themembers into sliding contacting relation with a spiral movement when thedirection of rotation is reversed; and a plurality of independentsprings arranged around the extended axes of the operating and operatedparts of said mechanism, and anchored to the members to provide rotarythrust between the members at several points around said axes.

1l. A mechanical silent tappet comprising two wafer-like membersarranged one above the other in confronting relation, and adapted to beinterposed between operating and operated parts of a valve-actuatedmechanism; the upper member having a depending annular flange on itsperiphery having a dust-tight and sliding telescoping t with theperiphery of the lower member; the flange defining a downwardly-facingopening at its bottom through which the lower member is insertable;camming means confined within the peripheries of the members forseparating them when one member is rotated relative to the other in onedirection; the camming means being shaped to gradually move the membersinto sliding contacting relation with a spiral movement when thedirection of rotation is reversed; and a plurality of independentsprings arranged around the extended axes of the operating and operatedparts of Said mechanism, and anchored to the members to provide rotarythrust between the members at several points around said axes; saidcamming means including ball bearings disposed between the members andaround the extended axes of the operating and operated parts of saidmechanism and providing substantially uniform ball bearing supportbetween the members.

12. A mechanical silent tappet comprising two disc-shaped membersmovable into face-to-face contact so as to transmit thrust from onemember directly to the other, and adapted to be placed between anoperating part and an operated part of a valve-actuating mechanism; theconfronting faces of the members having registering recesses withcam-shaped surfaces that extend from said faces to a spacedpredetermined distance therefrom; a ball bearing disposed in each pairof recesses; the pairs of recesses being arranged about the center ofthe members; the cam surfaces of each pair of recesses being slopedoppositely so that a relative rotation between the members in onedirection will cause the balls to ride upon the cam surfaces to separatethe members; and spring means for yieldingly urging the members in thedirection just mentioned; the recesses having suiiicient depth toentirely receive the balls and thus allow the members to come intoface-to-face contact with one another when the members are rotated intoa predetermined position relative to one another and thus relieve theballs from thrust.

13. A mechanical silent tappet comprising two disc-like members arrangedone above the other, and adapted to be placed between an operating andan operated part of a valve-actuating mechanism; the upper member havinga depending annular flange on its periphery having a dust-tight andsliding telescoping fit with the periphery of the lower member; theflange deiining a downwardly-facing opening at its bottom through whichthe lower member is insertable; the confronting faces of the membershaving registering recesses with cam-Shaped surfaces that extend fromsaid faces to a spaced predetermined distance therefrom; a ball. bearingdisposed in each pair of recesses; the pairs of recesses being arrangedabout the centers of the members; the cam surfaces of each pair ofrecesses being sloped oppositely so that a rotation between the membersin one direction will cause the balls to ride up on the cam surfaces toseparate the members; and a plurality of independent springs foryieldingly urging the members in the direction just mentioned toseparate the members.

CLIFTON L. STANCLIFF.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,452,276 Jerdone Apr. 17, 19231,631,563 rlitus June 7, 1927 1,790,999 Perkins Feb. 3, 1931 1,903,078Woolman Mar. 28, 1933 1,913,241 Kuse June 6, 1933

